JPH0369829A - Driving force transmission - Google Patents

Abstract

PURPOSE:To eliminate the highly frictional state of a friction clutch to seize it and prevent burning and any other damage by urging a piston by a pushing member, wherein a temperature sensing member is used, to cut off the intercommunication between a fluid chamber and a cylinder by the piston. CONSTITUTION:An annular second piston 18a is liquid-tightly and slidably inserted into a cylinder part 13d. The second piston 18a is urged by a plate spring 18 interposed between a support plate 13a and the second piston 18a to be seated at the bottom of the cylinder 13d, thereby cutting off the intercommunication between a fluid chamber and the cylinder 13d under a predetermined pressure. The plate spring 18b is made of bimetal or shape memory alloy, and is deformed into a flat shape at a preset high temperature to dissipate the pressure with respect to the second piston 18a and remarkably reduce the pressure of an operating piston 13 with respect to a friction clutch 10b. Therefore, the highly frictional state of the friction clutch 10b is eliminated to be burnt so that no other damage cannot be generated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a driving force transmitting device which is disposed between an inner and an outer rotating member that are coaxially and relatively rotatably located, and which transmits torque between these two members. Regarding equipment.

(Prior art) Such a driving force transmission device is disposed between a driving side rotating member and a driven side rotating member, and connects these two members so that torque can be transmitted to each other when these two members rotate relative to each other. A coupling mechanism used as a coupling mechanism for driving members, and a mechanism disposed between a driving side and a driven side rotating member, between a circumferential driving side rotating member, or between both driven side rotating members, and when these two members rotate relative to each other. The first type of coupling mechanism is mainly used in real-time four-wheel drive vehicles. The latter differential limiting mechanism is mainly provided at each differential in the vehicle.

However, as a conventional driving force transmission device,
As shown in Japanese Patent No. 240429, it is disposed between both inner and outer rotating members that are coaxially and relatively rotatably positioned,
a friction clutch that is actuated by the relative rotation of these two rotating members to generate a frictional engagement force that connects the two rotational members so that torque can be transmitted, and that increases or decreases the frictional engagement force in accordance with the applied axial pressing force; A pressing force generating means is provided for generating an axial pressing force corresponding to the relative rotation of both rotating members and applying it to the friction clutch, and the pressing force generating means is arranged between the two rotating members in a liquid-tight manner. an operating piston that is slidable in the direction and integrally rotatably assembled to the outer rotating member and faces the friction clutch; A driving force transmission device comprising: a fluid chamber in which a viscous fluid is sealed; and a rotor that includes one or more vanes extending in a radial direction and is integrally assembled to the inner rotating member in the fluid chamber. There is a device.

In this type of driving force transmission device, when relative rotation occurs between both rotating members, the working piston, which is assembled to be integrally rotatable with the outer rotating member, and the rotor, which is integrally assembled with the inner rotating member, are connected. Relative rotation occurs, and the viscous fluid within the containment chamber is forced to flow by the vane portion of the rotor in the fluid chamber, and pressure is generated within the containment chamber due to flow resistance and the like. That is, a pressure corresponding to the differential rotation speed is generated in the pressing force generating means. This pressure pushes the actuating piston in the axial direction, causing the friction clutch to be pressed and generating a frictional engagement force in the clutch that connects both rotating members in a torque-transmitting manner.

This frictional engagement force is proportional to the differential rotation speed, and a torque proportional to the differential rotation speed is transmitted between the two rotating members from one side to the other. Therefore, the driving force transmission device functions as a connection mechanism between the driving side rotating member and the driven side rotating member in one power transmission path of the four-wheel drive vehicle, and also between the driving side and driven side rotating member, It also functions as a differential limiting mechanism between rotating members or between both driven rotating members.

(Problems to be Solved by the Invention) By the way, in the above-mentioned type of driving force transmission device,
When a high differential rotation occurs between both rotating members, such as when a vehicle is stuck off-road, the friction clutch becomes in a high friction state and seizes or causes other burnout damage. It is therefore an object of the present invention to address such problems.

(Means for Solving the Problems) The present invention provides a driving force transmission device of the type described above, in which the actuating piston or the outer rotating member is provided with a cylinder portion that communicates with the fluid chamber, and a second piston is provided in the cylinder portion. is slidably inserted, and the piston is pressed by a pressing member to cut off communication between the fluid chamber and the cylinder part, and the pressing member acts as the pressing force when a predetermined high temperature is reached. It is characterized by employing a temperature sensitive member that eliminates or reduces the temperature.

(Operations and Effects of the Invention) According to this configuration, when the temperature of the pressing member is lower than a predetermined high temperature, the second piston cuts off communication between the fluid chamber and the cylinder part by the pressing force of the pressing member, and presses In the pressure generating means, a set pressing force is generated, the friction clutch is frictionally engaged, and torque is transmitted between the two rotating members in proportion to the differential rotation speed.

Therefore, when the vehicle becomes stuck and a high differential rotation occurs between both rotating members, the friction clutch becomes in a high friction state and becomes hot. When the friction clutch reaches a predetermined high temperature, the pressing member reaches a predetermined high temperature and eliminates or reduces the pressing force against the second piston. As a result, the second piston communicates the fluid chamber with the cylinder part, and a part of the viscous fluid in the fluid chamber flows into the cylinder part, and the filling rate of the viscous fluid in the fluid chamber decreases proportionally. As a result, the pressing force generated by the pressing force generating means decreases. For this reason, the pressing force on the friction clutch is significantly reduced, and the friction clutch is released from a high friction state and does not seize or cause other burnout damage.

(Example) Examples of the present invention will be described below based on the drawings.
The figure shows an embodiment of the driving force transmission device according to the present invention. As shown in FIG. 5, the driving force transmission device 10 is disposed in a rear wheel power transmission path of a real-time four-wheel drive vehicle.

In this vehicle, the front wheels are always driven and the rear wheels are driven when necessary. A transaxle 22 attached to one side of the engine 21 is equipped with a transmission and a transfer, and outputs the driving force from the engine 21 to an axle shaft 23. The power is output to the first propeller shaft 25 and drives the front wheels 24 . The first propeller shaft 25 is connected to a second propeller shaft 26 via the drive power transmission device 10, and these two shafts 25.2
6 is capable of transmitting torque, the driving force is output to the axle shaft 28 via the rear differential 27, and the two rear wheels are driven.

Thus, the driving force transmission device 10 includes a pressing force generating means 10a and a friction clutch 10b in an annular working chamber made up of an outer case 11 and an inner shaft 12.

The outer case 11 includes an inward flange portion 11b at one end of a cylindrical portion 11a having a predetermined length, the other end of the cylindrical portion 11a is open, and a threaded portion 11c is formed on the inner periphery of the other end. A retainer 15, which will be described later and which constitutes an outer rotating member together with the outer case 11, is screwed onto the threaded portion 11c. The inner shaft 12 includes an outward flange portion 12b on the outer periphery of the intermediate portion of a stepped cylindrical portion 12a having a predetermined length, an outer spline portion 12c extending in the axial direction is formed on the outer periphery of the flange portion 12b, and the cylindrical portion An internal spline portion 12d extending in the axial direction is formed on the inner periphery of one end of the spline 12a. In such an inner shaft 12, one end of the cylindrical portion 12a is connected to the inward flange portion 1 of the outer case 11.
1b in a fluid-tight and rotatable manner;
It is rotatably supported by the outer case 11 via a retainer 15. The inner shaft 12 is fixed at its inner spline portion 12d by fitting into the spline 26a at the tip of the second propeller shaft 26, and is fixed to the outer case 1.
1 is fixed to the rear end of the first propeller shaft 25.

The pressing force generating means 10a includes an operating piston 13 and a rotor 14.
and a retainer 15, and a friction clutch 10b
The clutch is of a wet type multi-plate clutch type and consists of a large number of clutch plates 16 and clutch discs 17. Each clutch plate 16 has a spline portion on its outer periphery fitted into a spline portion lid provided on the inner periphery of the outer case 11, and is assembled to the case 11 so as to be integrally rotatable and movable in the axial direction. Each clutch disc 17 has a spline portion on its inner circumference fitted into an outer spline portion 12c of the inner shaft 12, is located between each clutch plate 116, and is assembled to the shaft 12 so as to be rotatable integrally and movable in the axial direction. It is being

A predetermined amount of clutch oil and gas are sealed in the storage chamber R1 of the clutch plate 16 and the clutch disc 17.

The actuating piston 13 constituting the pressing force generating means 10a is attached to the outer case 1 as shown in FIGS. 1, 3, and 4.
The inner circumference of the other end side of the cylindrical portion 11a of 1 is rotatable and slidable in the axial direction in a liquid-tight manner, and the outer circumference of the inner shaft 12 is rotatable and slidable in the axial direction in a liquid-tight manner. They are movably assembled, and an annular support plate 13a fixed to the side face faces and abuts against a clutch plate 16 at the rightmost end in the figure. As shown in FIGS. 1 and 2, the rotor 14 includes two vane portions 14b extending in the radial direction at positions 180° apart from each other on the outer periphery of an annular boss portion 14a. 14a, it is integrally assembled to the outer periphery of the cylindrical portion 12a on the inner shaft upper 2. The rotor 14 is formed to have approximately the same thickness as the depth of the annular recess 13b provided on the other side of the actuating piston 13, and is fitted into the annular recess 13b. Retainer 1
5 is provided with a threaded portion 15a on the outer periphery of the other end, and is fitted to the outer periphery of the other end of the cylindrical portion 12a of the inner shaft 12 so as to be slidable and rotatable in the axial direction in a fluid-tight manner, and is connected to the outer case 11. The threaded portion 15a of the outer case 11 is screwed into the threaded portion 11c of the outer case 11 so that it can move forward and backward, and is liquid-tight. In this retainer 15, the position in the axial direction is adjusted and fixed to the outer case 11 by caulking means,
The side surface 15b thereof contacts the annular outer edge surface 13c on the other side of the working piston 13, and the side surface 15b and the annular recess 13b of the working piston 13 form a fluid chamber in which the rotor 14 is located. A predetermined amount of high viscosity fluid such as silicone oil is sealed in this fluid chamber, and the rotor 14
The outer periphery of the vane portion 14b is in liquid-tight contact with the inner periphery of the annular recess 13b, and a minute gap is formed between both side surfaces of the vane portion 14b, the other side surface 13b1 of the annular recess 13b, and one side surface 15b of the retainer 15. The fluid chamber is divided into two retention chambers R2.

An annular cylinder portion 13d is formed on one side of the actuating piston 13, and the cylinder portion 13d communicates with the fluid chamber via a plurality of communication holes 13e. An annular second piston 18a is fluid-tightly and slidably inserted into the cylinder portion 13d, and the second piston 18a is pressed by a disc spring 18b interposed between the support plate 13a and the cylinder. It is seated on the bottom of the portion 13d with a predetermined pressing force. Thereby, the second piston 18a blocks communication between the fluid chamber and the cylinder portion 13d with a predetermined pressing force. The disc spring 18b is made of bimetal or shape memory alloy, and when it reaches a predetermined high temperature, it deforms into a flat plate shape and loses its pressing force against the second piston 18a.

In the driving force transmission device 10 having such a configuration, the second piston 8a is normally connected to the cylinder portion 13d as shown in FIG.
communication with the fluid chamber is cut off by a predetermined pressing force, and
When relative rotation occurs between the second propeller shafts 25 and 26, torque is transmitted. That is, when relative rotation occurs between these two shafts 25 and 26, the outer case 11, the operating piston 13, and the retainer 15, which are assembled to the first propeller shaft 25 so as to be able to rotate integrally with each other,
Relative rotation occurs between the inner shaft 12 and the rotor 14, which are assembled to the second propeller shaft 26 so as to be rotatable together. Therefore, in the fluid chamber of the pressing force generating means 10a, the viscous fluid in the retention chamber R2 is forced to flow at a speed proportional to the relative rotational speed, and the viscous fluid in the retention chamber R2 moves relative to each other sequentially in the circumferential direction. Due to the resistance, a pressure distribution is generated in which the pressure is gradually increased from the downstream end of the vane section 14b to the upstream end of the next vane section 14b. The increased pressure portion of this pressure distribution increases in proportion to the differential rotation speed, and presses the actuating piston 13 in the axial direction. As a result, the actuating piston 13 presses the friction clutch 10b to frictionally engage each clutch plate 16 and clutch disk 17 that constitute the friction clutch 10b via the clutch oil. As a result, in the friction clutch 10b, torque proportional to the differential rotation speed is transmitted from the outer case 11 to the inner shaft 12, and the vehicle enters a four-wheel drive state. Furthermore, in this four-wheel drive state, differential rotation between the front and rear wheels is allowed, and tight corner braking is also prevented from occurring.

By the way, in the driving force transmission device 10, when the vehicle becomes stuck and a high differential rotation occurs between the outer case 11 and the inner shaft 12 and the friction clutch 10b reaches a predetermined high temperature, the disc spring 18b moves to a predetermined temperature. The second piston 18a reaches a high temperature, deforms into a flat plate shape, and loses its pressing force against the second piston 18a.

As a result, the pressurized viscous fluid in the retention chamber R2 of the fluid chamber flows into the cylinder portion 13d while sliding on the second piston 18a, as shown in FIG. significantly reduces the filling rate. As a result, the retention chamber R2
The pressure generated therein is suddenly and significantly reduced, and the pressing force of the actuating piston 13 against the friction clutch 10b is significantly reduced. Therefore, the high friction state of the friction clutch 10b is eliminated, and seizure or other burnout does not occur.

Further, the disc spring 18b applies and releases the pressing force to the second piston 18a by temperature change, and can apply the pressing force more efficiently than when applying the pressing force to the operating piston 13. .

In the above embodiment, the operating piston 13 is provided with the cylinder portion 13d, and the second piston 18a is fitted into the cylinder portion 13d and biased by the disc spring 18b. However, in the present invention, the beam retainer 15 may be provided with a cylinder portion, the second piston may be inserted into the cylinder portion, and biased by a pressing member such as a spring member. Further, in the above embodiment, a fluid chamber is formed between the actuating piston 13 and the retainer 15, and the rotor 14 is disposed in the fluid chamber. The rotor 14 may be disposed in the fluid chamber, and the friction clutch 10b may be disposed between the actuating piston and the retainer 15.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a driving force transmission device according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken in the direction of arrows - ■ in FIG.
Figures 4 and 4 are enlarged cross-sectional views of the main parts of the same device, and Figure 5.
The figure is a schematic diagram of a vehicle that employs the same device. Explanation of symbols 10... Drive force transmission device, 10a... Pushing force generating means, 10b... Friction clutch, 11... Outer case, 12... Inner shaft, 13... Working piston, 13d...・・Ring part, 13e・Communication hole, 1
4...Rotor, 14b/vane portion, 15...retainer, 16...clutch plate, 17...clutch disc, 18a...second piston, 18b...disc spring, 25.26... ·Propeller shaft.

Claims (1)

[Claims] It is disposed between the inner and outer rotating members that are coaxially and relatively rotatably positioned, and is actuated by the relative rotation of these rotating members to generate and apply a frictional engagement force that connects the two rotating members so that torque can be transmitted. A friction clutch that increases or decreases the friction engagement force in accordance with an axial pressing force, and a pressing force generating means that generates an axial pressing force in accordance with the relative rotation of both rotating members and applies it to the friction clutch, The pressing force generating means is configured to include an actuating piston that is slidable liquid-tightly in the axial direction between the two rotary members and integrally rotatable with the outer rotary member and faces the friction clutch; and the actuating piston, the fluid chamber having a predetermined interval in the axial direction and containing a viscous fluid therein, and one or more vanes extending in the radial direction, the inner rotating member in the fluid chamber. A driving force transmission device consisting of a rotor and a rotor integrally rotatably assembled to the
A cylinder portion communicating with the fluid chamber is provided in the actuating piston or the outer rotating member, and a second piston is slidably inserted into the cylinder portion, and the piston is pressed by a pressing member, so that the second piston is pressed by a pressing member. A driving force transmission device characterized in that a temperature sensitive member is used as the pressing member to cut off communication between the fluid chamber and the cylinder portion and to eliminate or reduce the pressing force when a predetermined high temperature is reached.